Ed Sirett wrote in news:finevc$1ej
:

On Thu, 29 Nov 2007 16:06:41 +0100, John wrote:

(Andrew Gabriel) wrote in
:

In article ,


at the moment the boiler thermostat is set to 65 deg and
the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat
to
max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when
the return
water
temp to the boiler is 54c

It still gets even more efficient at lower temperatures
than
that.
My condensing boiler runs at 40C return temperature for
heating,

True but I was replying to OP and making some assumptions
based on his
plumbers comments
I.e. I would be surprised if radiators have been replaced
and resized to
allow such a low return temp. And I think it's only the
ecomax combi
that has a separate HW temp setting.


I believe AG may have done that for himself. I doubt that
serviceable
radiators are worth replacing with oversized units on fuel
efficiency
grounds. But with a new system you would try to
design/guesstimate for
cooler return temps.


Yes that was the assumption I was making in my reply to the OP


Many many combis have seperate controls for heating and the
MAXIMUM HW
temp, even really low end units.


I wasn't suggesting that the ecomax combi was the only one
with a separate HW control, more that the OPs ecomax system or
heatonly boiler did not have this facility whereas the combi
variant does.



There are only a few quite high end models for non combis
which have
different setting for HW mode and heating mode, and then
only in the
larger units.

Yes like Vaillants own EcoTec plus 415, although hardly
classified as large at 15Kw.
Unless you were referring to case dimensions :P


John.